Acidic fluorine-containing poly (siloxane amideimide) silica hybrids

ABSTRACT

The present invention discloses an acidic fluorine-containing hybrid having a uniform distribution of an organic and an inorganic components prepared by a sol-gel process. The organic component is a fluorine-containing poly(siloxane amideimide) having a good processing ability, gas permeability, mechanical properties, and chemical stability. The inorganic component is silica having good heat resistance and moisture resistance. The hybrid has excellent properties, such as a good film formation property, a high gas selectivity, a low dielectric constant, a good resistance to scraping, and a good transparency, etc., and can be used in making industrial products, such as gas detection films, sensors, encapsulation material, photoelectrical communication material, and biomedical material, etc.

FIELD OF THE INVENTION

[0001] The present invention relates to the synthesis of a novel acidicfluorine-containing poly(siloxane amideimide)-silica hybrid.

BACKGROUND OF THE INVENTION

[0002] Due to its excellent dielectric and mechanical properties at ahigh temperature and excellent thermo-oxidation stability at 180˜220° C.a poly(amideimide) meets the basic application conditions, such as hightemperature resistance and insulation property, required by wires andcables. U.S. Pat. No. 5,932,351 discloses a poly(amideimide) having agood mechanical strength at a high temperature, which can be used as athermo-resistant adhesive. Furthermore, U.S. Pat. No. 5,939,520discloses a gas mixture separation technique by using apoly(amideimide). However, the applications of a poly(amideimide) arelimited because the poly(amideimide) has a relatively high waterabsorbency (˜4 wt %) and thermal expansion (˜5×10⁻⁵ K⁻¹).

SUMMARY OF THE INVENTION

[0003] In order to improve the properties of the poly(amideimide), thepresent invention uses a sol-gel process to synthesize an acidicfluorine-containing poly(siloxane amideimide) silica hybrid, which is anorganc-inorganic material. An organic-inorganic hybrid synthesizedaccording to the present invention has the following structure:

[0004] wherein

[0005] R₁ is from

[0006]  and R₁ contains a fluoro substituent;

[0007] R₂ is from

[0008]  and R₂ contains a fluoro substituent;

[0009] R₃ is

[0010]  wherein R′₁

R′₂

R′₃ and R′₄ are C1-C4 alkyl or phenyl, R′₅ and R′₆ are C1-C6 alkylene orphenylene, and n=1˜10;

[0011] R″₁ is C1-C4 alkylene or phenylene; and

[0012] R″₂ is C1-C4 alkyl or phenyl.

[0013] Preferably, R₁ is

[0014] Preferably, R₂ is from

[0015] Preferably, R′₁

R′₂

R′₃ and R′₄ are methyl, R′₅ and R′₆ are propylene group, and n=1.

[0016] Preferably, R″₁ is a propylene group, and R″₂ is methyl.

[0017] The hybrid of the present invention has a stable bonding betweenthe organic poly(amideimide) and the inorganic silica, while theinorganic silica is uniformly distributed in the organic polymer,thereby improving the mechanical properties, the chemical resistance,and the dimensional and thermal stabilities of the material. This typeof organic-inorganic hybrid compound exhibits excellent complementaryproperties, and can effectively enhance the transparency and wearresistance of the material. The incorporation of the inorganic materialis helpful in reducing the permeation activation energy of a specificgas, so that the gas selectivity becomes higher (i.e. selectivepermeation of a specific gas component in a multi-component gasmixture), and thus increases the gas separation efficiency.

[0018] On the other hand, the backbone of the poly(amideimide) can beintroduced with functional or active groups, e.g. siloxane,fluoro-containing hydroxy, etc., to broaden the application scope of thepoly(amideimide). The direct attachment of a fluoro-containing sidechain (e.g. trifluoromethyl, CF₃) to the backbone of poly(amideimide)can break the regularity of the molecular chain and reduce the meltingpoint of the polymer, such that the material also possesses a goodsolubility, a good refractive index, a low water absorbency, a lowthermal expansion, and a low dielectric constant value, whilemaintaining its thermal stability.

[0019] The introduction of a soft siloxane monomer in thepoly(amideimide) structure can effectively increase the gas permeabilityand enable the poly(amideimide) exhibiting a lower water absorbency andsurface energy, thereby increasing the adhesion and toughness of apoly(amideimide) membrane. While exposing to air, a protective layerwill be formed on the poly(siloxane amideimide), which is advantageousin the application of this material as a micro-electronic insulationmaterial. Furthermore, the hybrid of the present invention contains anacidic hydroxyl group (—OH), which can adsorb a basic gas, which isparticularly advantageous to the separation of an acid/basic gasmixture.

[0020] Various successful modification techniques of the acidicfluorine-containing poly(siloxane amideimide)-silica hybrid of thepresent invention have greatly improved the properties and the potentialin many applications of the poly(amideimide). Furthermore, additionalreactants may be used to react with the acidic fluorine-containingpoly(siloxane amideimide)-silica hybrid of the present invention,creating a series of organic-inorganic hybrid derivatives. Therefore,the hybrid material according to the present invention is versatile inuse, and can be easily extended to other applications.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0021]FIG. 1 is an IR spectrum of a fluorine-containing poly(siloxaneamideimide)-silica hybrid according to the present invention, whereinthe concentrations of the reactant (E) (Si(OR₄)₄) are, respectively, 0

25

30

35

40 and 45 wt %.

[0022]FIG. 2 is a ¹³C-NMR spectrum of a fluorine-containingpoly(siloxane amideimide)-silica hybrid according to the presentinvention.

[0023]FIG. 3 is a ²⁹Si-NMR spectrum of a fluorine-containingpoly(siloxane amideimide)-silica hybrid according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention provides a novel acidic fluorine-containingpoly(siloxane amideimide)-silica hybrid with the following formula (D),which can be synthesized by a method comprising the following steps (a)to (e), which are described by referring to the following Scheme 1:

[0025] a) reacting a fluoro-containing dianhydride (reactant A) with ahydroxy-containing diamine (reactant B) at a molar ratio of about 2:1 toform an amic acid (product A);

[0026] b) reacting a siloxane diamine (reactant C) with the amic acidproduct A from step a) at a molar ratio of about 1:1 to form a siloxaneamic acid (product B);

[0027] c) reacting a dialkoxyl alkyl amino silane with the siloxane amicacid product B from step b) at a molar ratio of about 2:1 to form afluoro-containing poly(siloxane amic acid) having two terminals ofdialkoxyl alkyl silane (product C);

[0028] d) reacting a tetraalkoxyl silane (reactant E) with thedialkoxyl-alkyl-silane terminated poly(siloxane amic acid) (product C)from step c); and

[0029] e) heating the product mixture of step d), thereby obtaining afluorine-containing poly(siloxane amideimide)-silica hybrid (product D).

[0030] wherein

[0031] R₁ is from

[0032]  and R₁ contains a fluoro-substituent;

[0033] R₂ is from

[0034]  and R₂ contains a fluoro-substituent;

[0035] R₃ is

[0036]  wherein R′₁ to R′₄ is C1-C4 alkyl or phenyl, R′₅ and R′₆ isC1-C6 alkylene or phenylene, and n=1˜10;

[0037] R″₁ is C1-C4 alkylene or phenylene;

[0038] R″₂ is C1-C4 alkyl or phenyl;

[0039] R″₃ is C1-C4 alkyl;

[0040] R₄ is C1-C4 alkyl.

[0041] Preferably, the reactant (A) is4,4′-(hexafluoroisopylidene)diphthalic anhydride (hereinafterabbreviated as 6FDA) or 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride (hereinafter abbreviated as6FDEDA).

[0042] Preferably, the reactant (B) is2,2′-bis(3amino-4-hydroxyphenyl)hexafluoropropane (hereinafterabbreviated as AHHFP).

[0043] Preferably, the reactant (C) is 1,3-bis(3-aminopropyl)tetramethyldisiloxane (hereinafter abbreviated as DAPrTMDS).

[0044] Preferably, the reactant (D) is 3-aminopropylmethyldiethoxysilane(hereinafter abbreviated as APrMDEOS).

[0045] Preferably, the reactant (E) is tetramethoxysilane (hereinafterabbreviated as TMOS).

[0046] Without further elaboration, it is believed that the abovedescription has adequately enabled the present invention. The followingspecific examples are, therefore, to be construed as merelyillustrative, and not limitative of the remainder of the disclosure inany way whatsoever.

EXAMPLE 1 Synthesis of Product A

[0047] In a round bottomed flask filled with nitrogen, 6FDA wasdissolved in a mixed solvent of N,N-dimethylacetamide (DMAc) and tolueneinto a 10˜25 wt % 6FDA solution. The same method was used to prepare a10˜25 wt % AHHFP solution. The AHHFP solution was added into the 6FDAsolution, and the resultant mixture was stirred with a stirrer at roomtemperature for reaction for 18˜30 hours, thereby obtaining a solutionof the product A.

EXAMPLE 2 Synthesis of Product B

[0048] DAPrTMDS was added to the solution of product A from Example 1,and the resulting mixture was stirred for reaction for 1˜4 hours,thereby obtaining a solution of product B.

EXAMPLE 3 Synthesis of Product C

[0049] APrMDEOS was added to the solution of product B from Example 2,and the resulting mixture was stirred for reaction for 936 hours,thereby obtaining a solution of product C.

EXAMPLE 4 Synthesis of Product D

[0050] A H₂O/TMOS solution was prepared. The H₂O/TMOS solution was addedto the solution of product C from Example 3 in an amount so that theresulting mixture contained 20˜50 wt % of TMOS. The resulting mixturewas stirred at room temperature for reaction for 18˜30 hours, therebyobtaining a solution of product D. The solution of product D was pouredonto a Teflon plate, where it was dried at 50˜110° C. under atmosphericpressure for 18˜30 hours, and u at 80˜150° C. nder vacuum for 1˜5 hours,at 100˜300° C. under vacuum for 2˜5 hours, at 200˜350° C. under vacuumfor 1˜4 hours, and at 100˜300° C. under vacuum for 1˜5 hours, therebyobtaining a solid product D (fluorinated poly(siloxaneamideimide)-silica hybrid).

[0051] IR Spectrum and ¹³-NMR Spectrum Identification of Product D

[0052] The structure of the product D was identified by an IR spectrum(FIG. 1) and a ¹³C-NMR spectrum (FIG. 2). The IR spectrum shows thestretching vibration of Si—OH, H₂O, N—H, and O—H in 2700˜3500 cm⁻¹; asymmetric stretching vibration of imide C═O at 1778 cm⁻¹; an asymmetricstretching vibration of imide C═O at 1713 cm⁻¹; a stretching vibrationof amide C═O at 1622 cm⁻¹; a stretching vibration of C—N at 1392 cm⁻¹; aplanar bending vibration of imide C═O at 722 cm⁻¹; an absorption peak ofphenyl ring at 1519 cm⁻¹; an asymmetric stretching vibration of cyclicSi—O—Si at 1062 cm⁻¹; and a stretching vibration of Si—OH at 964 cm⁻¹.The results identify the formation of a three-dimensional —Si—O—Si—network structure. A small amount of —SiOH group exists in this networkstructure, which contains an imide structure. The ¹³C-NMR shows that theresonance frequency of the carbon atom on the C═O of imide was 166 ppm(f); 154 ppm (h) for the carbon atom connecting to an aromatic hydroxy;140˜118 ppm (I, j, k) for aromatic carbons; 65 ppm (e) for a quaternarycarbon; 41 ppm (d) for —NCH₂—; 21 ppm (b) for —CH₂—; 15 ppm (c) for—CH₂Si—; −1.0 ppm (a) for —SiCH₃; and the absorption peaks of DMAc(solvent) were 38, 35 and 20 ppm(*). The results indicate the formationof an imide structure.

[0053]²⁹Si-NMR Spectrum Identification of Product D

[0054]FIG. 3 is a ²⁹Si-NNR spectrum of the product D, wherein Q⁴generats a resonance at −108 ppm, Q³ generats a resonance at −100 ppm,D² generates a resonance at −18 ppm, M¹ generates a resonance at 12 ppm.Q⁴ indicates that there are four —O—Si groups on Si and no other organicside chain (i.e. Si(OSi)₄). Q³ indicates that there are three —O—Sigroups on Si and one organic side chain (i.e. ROSi(OSi)₃). D² indicatesthat there are two —O—Si groups on Si and two organic side chains (i.e.Si(OSi)₂R₂). M¹ indicates that there is one —O—Si group and threeorganic side chains (i.e. Si(OSi)R₃) D ² and M¹ are related to siloxanechain segments. The Si atoms of Q³ and Q⁴ pretain to a silica networkstructure. The calculations from the peak values of ²⁹Si-NMR indicatethat the conversion (D_(c)) of tetramethoxysilane was higher than 95%.Under the condition where no acid matter was added, this identified thatthe copolymer is an acidic polymer. A spin relaxation locking of across-polarization technique was used to transmit the magnetic signal ofa polarized ¹H to ²⁹Si; and then the variation of the peak value of a Sinucleus was used to obtain a spin-lattice relaxation time, T_(lρ) ^(H)and T_(1  ρ)^(Si),

[0055] of the magnetization of ¹H and ²⁹Si under the cross polarizatointime (T_(SiH)) and the spin coordinates of the ¹H-²⁹Si. The relationshipL={square root}{square root over (6DT_(lρ) ^(H))} was used to obtain thelength of the spin-diffusion path (L). The result indicated that thelength of the spin-diffusion path did not greatly decrease along with anincrease in the content of the reactant tetramethoxysilane. L, valueswere all smaller than 5 nm. This indicated that the distribution of theorganic and inorganic components in this hybrid was rather uniform.

[0056] Although the present invention has been described with referenceto specific details of certain embodiments thereof, it is not intendedthat such details should be regarded as limitations upon the scope ofthe invention except as and to the extent that they are included in theaccompanying claims. Many modifications and variations are possible inlight of the above disclosure.

What is claimed is:
 1. An organic-inorganic hybrid having the followingstructure:

wherein R₁ is from

 and R₁ contains a fluoro substituent; R₂ is from

 and R₂ contains a fluoro substituent; R₃ is

 wherein R′₁

R′₂

R′₃ and R′₄ are C1-C4 alkyl or phenyl, R′₅ and R′₆ are C1-C6 alkylene orphenylene, and n=1˜10; R″₁ is C1-C4 alkylene or phenylene; and R″₂ isC1-C4 alkyl or phenyl.
 2. The organic-inorganic hybrid as claimed inclaim 1, wherein R₁ is


3. The organic-inorganic hybrid as claimed in claim 1, wherein R₂ isfrom


4. The organic-inorganic hybrid as claimed in claim 2, wherein R₂ isfrom


5. The organic-inorganic hybrid as claimed in claim 3, wherein R′₁

R′₂

R′₃ and R′₄ are methyl, R′₅ and R′₆ are propylene group, and n=1.
 6. Theorganic-inorganic hybrid as claimed in claim 4, wherein R′₁

R′₂

R′₃ and R′₄ are methyl, R′₅ and R′₆ are propylene group, and n=1.
 7. Theorganic-inorganic hybrid as claimed in claim 5, wherein R″₁ is apropylene group, and R″₂ is methyl.
 8. The organic-inorganic hybrid asclaimed in claim 6, wherein R″₁ is a propylene group, and R″₂ is methyl.